Method and means for slotting tubes



Jan. 3l, 1933. G. sPATTA METHOD AND MEANS FOR SLOTTING TUBES Filed Deo. 30, 1929 4 Sheets-Sheet l Jan. 31, 1933. G. sPATTA METHOD AND MEANS FOR SLOTTING TUBES Filed Dec. 50, 1929 4 Sheets-Sheet 2 jan. 31, 1Q33. G, SPATTA 1,895,589

METHOD AND MEANS FOR SLOTTING TUBES Filed Dec; 30, 1929 4 Sheets-Sheet 3 Jan. 31, 1933. G, SPATTA gg METHOD AND MEANS Foa sLoTTING TUBES Filed Dec 50. 1929 4 Sheets-Sheet 4 Patented Jan. 3l, 1933 UNITED YSTATES PATsN'r orf-ICE j GEORGE SPATTA, OF BUCHANAN, MICHIGAN, ASSIGNOR TO CLARK EQUIPMENT COMPANY, F BUCHANAN, MICHIGAN, A CORPORATION 0F MICHIGAN METHODv AND MEANS FOR SLOTTING- TUBESl Application filed December 30, 1929. Serial No. 417,581.

This invention relates to method of and means for slotting tubes.

In my copending application, Serial N o. 416,537, iiled December 26, 1929, I disclosed a method of forming banjo axle housings for motor vehicles from seamless steel tubings, and the present invention relates to a step .in the process of the manufacture of such axles and to the machine for performing this step.

Thilo the invention is primarily concerned with the performance of a. step in the method pointed out in my copending application, and While the drawings contained herein disclose a machine primarily intended for the performance of the slotting operation of said method, the invention is obviously applicable in many other instances, in fact it can be ,n i applied to any process wherein a tubing is to be slotted.

The seamless steel tubing used in the manufacture of axle housing, in itsinitial state, is usually a piece of tubing of from four to iive feet in length and from three to four inches in diameter and having a Wall thickness of approximately three-sixteenths of an inch. Of course, the length, diameter and Wall thickness of the tubing will be varied to meet the requirements of the finished housing, and the machine or machines employed in the performance of a step in the process of manufacture o-f such a housing must be sufficiently adjustable to permit their being adapted to the various sizel tubings used to manufacture various size housings.

The first step in the process of manufacture of such a housing` is the slotting of the tube to form an opening which is subsequently lf formed to a circular shape to fo-rm the inner perimeter of the banjo opening in the housing. The perimeter of the slot so formed must be approximately the same as the perimeter of the finished opening to avoid undue M, stretching or gathering of the metal during the processes of forming of the banjo section.

Since the inside diameter of the tube is rather small, I find it expedient to perform the slotting operation in three steps, the first sten res iltingr in the piercing of a Working f hole through` the tube, that hole being located centrally of the finished slot. This step of the operation of the process can be successfully carried out with an internal die fitted inside of the tube and an external punch registering With this die to shear the Wall of the tube and form the Working hole through it.

Because of the smallness of the inside diameter of the tube, I find itexpedient to perform the second step of the process on a horn punch which is fitted inside of the tube and registers With an external die to shear the tube Wall and form a slot in it. The horn punch is operated by a pressure pin projected through the Working hole that has been previi ously pierced in the tube Wall', and the horn 65' punch and its external die are shaped to give the desired shape to the slot that they pierce in the tube Wall.

After the slot has thus been formed in f one side of the tube, the tube is turned through V180" on the horn punch, and that tube adjusted with respect to the punch so that the punch is in position to punch a sec- Ond slot in the tube Which is located exactly opposite to the first slot. Pins are provided onthe horn punch to facilitate this alignment, and that punch is operated by the pressure pin which is now projected through the finished slot in the first Wall of the tube.

With a, tube having a Wall thickness as small as three-sixteenths of an inch, the slotting and punchingnoperations performed in this step of `the process can be performed With the tube cold, Without producing excessive Wear on the punch and die.

, The machine for carrying out this step] of the process preferably comprises a clevis like frame having an operating plunger mounted in the upper end clevis, that plunger preferably being operated mechanically in the manner of a punch press, although ay hydraulically operated punch may be employed. The hydraulic punch is, of course, slower and its use is not therefore, advantageous except when the Wall thickness to be pierced isvvery great.y

A bed plate is mounted on the loWer end clevis, With the free ends of the horn die and horn punch adjacent this bed plate but normally held away from it sufficiently to perapo mit insertion of the tubes around the horn die and horn punch and between it and the bed plate. The horn die and horn punch are pivoted to the frame at one side of the bed plate, and springs are provided and tensioned to raise the free end of the devices off the bed plate. j

An external punch is carried by the plunger and registered with the horn die to perform the first step of the process, and an external die is mounted on the bed plate in registration with the horn punch to carry out the second and third steps of the process. The horn die is operated by a pressure pin carried by the plunger.

Suitable guides are provided on the pivoted end of the horn die and horn punch to properly locate the tube on the devices so that the holes punched by the punches and dies will be properly located lengthwise of the tube.

Now to acquaint those skilled in the art with the teachings of my invention, reference is made to the accompanying drawings inwhich a preferred embodiment of the ma chine/for carrying out the steps of the process is shown by way of example and in which:

Figure 1 is a side elevational view of the dies and punches mounted in the machine frame work;

Figure 2 is a plan view of the bed plate of the machine and dies and punches mounted thereon; V

Figure 3 is an end view of the punches and dies taken from the working end of the machine;

Figure 4 is a cross-sectional view taken along the line 4-4 of Figure 2; p

Figure 5 is a cross-sectional view taken along the line 5-5 of Figure 2, Figures 4 and 5 together showing the details of the pivotal mounting of the horn die and horn punch;

Figure 6 is a cross-sectional view taken along the line 6 6 of Figure 2 showing the details of the horn die and external punch registering therewith; Figure 7 is a similar cross-sectional view taken along the line 7-7 of Figure 2 and showing the details of the horn punch and external die registering therewith;

Figure 8 is a cross-sectional view taken lalong the line 8 8 of Figure 2 and showing the details of the horn die and horn punch and their cooperating punch and die respectively;

Figure 9 is a perspective view ofthe tube blank used in this process;

Figure 10 is a perspective view of the blank after the first step of the process has been performed; and Figure 11 is a perspective view of the tube blank after the second step of the process has been performed.

Referring now to the drawingsin more detail, the machine in which the dies for slotting the tubes are placed preferably comprises a heavy duty mechanically operated punch press which is shown fragmentarily in Figure 1, and comprises the upper end clevis 1 and a. lower end clevis 2. The operating plunger 3 is mounted in the upper end of the vclevis and the bed plate 4 in the lower end, as is the custom in punch presses of this kind. The particular type of press employed can be varied greatly within the teachings of my invention and I have not, therefore, .shown the details of this press in thedrawings sincey the inclusion of these details would only tend to unnecessarily complicate the drawings. A bed pla-te 4 is bolted to the end clevis 2 by Vbolts 5 to rigidly and immovably support it thereon. The bed plate 4 comprises a generally rectangular member having an enlarged edge end which is bolted to the machine frame. At the smaller end of the bed plate, which projects laterally from the frame of the machine, are mounted the support blocks 6,7 and 8 through which the pivot shaft 9 is projected to pivotally support the extreme end of the horn die 10 and the horn punch 11. If desired the support blocks 6, 7 and 8 may be formed integral with the bed plate 4, although separate blocks suitably attached to that bed plate may be used if de* sired. Y

A spring support plate 12 is disposed across the top of the blocks 6, 7 andl 8 adjacent the frame of the punch press, that plate being attached to those blocks in any preferred manner such as by the bolts 13. This spring plate 12 serves as a support for the coil springs 14 and 15 which are held thereon by the bushing blocks 16 and 17 which support the lower end of the springs and serve as a guide for the operating pins 18 and 19. The operating pin 18 is pivotally connected as at 2O to the horn die 10, and is urged upward by the tension of the spring 14 which is placed under compression by tightening the nut 21 down upon the collar 22 which engages the upper edge of the spring. By this arrangement the. spring 14 urges the horn die in a counter-clockwise direction about its pivot 9 tending to keep the free end of thatdie oli' the base block of the press, as will presently appear. Similarly the operating pin 19 is pivotally connected by the pivot 23 to the horn punch 11 and is urged upward by the spring 15 which bears against the plate 24 which in turn bears against the nut 25 threaded on the upper end of the shaft 19. The spring l5 is thus made to urge the horn punch in a counter-clockwise direction about its pivot 9 to keep it off the registering die, in a manner which will likewise presently appear.

The spring pla-te 12 also serves as a support for the length gauge 8O which is preferably an Leshaped member bolted to the spring plate 12 by the bolt 31 and having its lower end 32 interposed between the horn punch and horn die in such a position that a tube slipped over this punch or die will engage the lower end 32 of the gauge to definitely locate the end of the tube with respect to the p-unch and die. A slot 33 is provided in the upper arm of the gauge to permit slight adjustment of this gauge in order to compensate for variation in the lengths of tubes used in the machine.

The spring plate 12 also serves as a support for the adjusting nuts 34 and 35 which are preferably set screws threaded through the plate 12 and projecting beyond its lower edge to serve. as a stop to limit the upward move ment of the horn die 10 and the horn punch 11, respectively. By suitable adjustment of these screws the free end of the die and punch can be properly located with respect to their cooperating stationary members on the bed plate of t-he machine.

The horn die 1() and the horn punch 11 are constructed of substantially cylindrical members of diameter sufficiently small to permit a tube to be readily slipped over them. In the preferred embodiment of the machine shown by way of example the members l0 and 11 are slightly less than three inches in diameter to permit their free movement within a three inch steel tubing. The die 10 and punch 11 must also be of sufficient lengt-h that they will project into the tube suiiiciently far to properly locate the slot-s they are to form with respect to the longitudinal dimension of the tube. Inv tubes used in the formation of axle housing, the slots are placed at the exact center of the tube and since that tube is between four and live feet long, the length of the die and punch 10 and 11 must be approximately half that amount.

The ends of the horn die 10 and of the horn punch 11, which register with the supporting blocks 6, 7 and 8, are machined rectangular so that they present broad flat surfaces in engagement. with these blocks. The edges of the blocks are machined perpendicular to the bed plate 4, and this engagement of the two flat surfaces insures that all movement of the members 10 and 11 about the pivot 9 will be in planes perpendicular to the bed plate. The broad flat bearing surface in the supporting block resists any tendency of the die and punch to turn under the stress of shearing the walls of tubes.

As will be best seen in Figures 1, 2, 3, 6, 7 and 8, the horn die 10 is mounted in front of the horn punch 11, that is toward the forward or working side of the punch press. The horn die comprises in addition to the cylindrical member 10 a hardened die member 40 which is set in a recess 41 near the free end of the die member 10. The inside diameter of the die 40 is accurately machined to fit the punch 42, and is preferably tapered as at so that the slug of metal sheared from the tube by the entrance of the punch 42 into the die 40, will fall freely through t-he die into the opening 45 disposed below the die. The punch 42 is mounted upon a punch supporting plate 46 and held therein by the set screw 42', or by any other preferred means. The plate 46 is in turn mounted on the bottom end of the plunger 3 of i the punch press by bolts 46 and is operated in a vertical direction by an operation of the press as is well understood by those skilled in the art. The die 40 and the punch 42 are preferably tool steel hardened to the proper temper for piercing the walls of the cold tube 44.

Adjacent the free end of the horn die 10 is an anvil block 50 which is fitted into transverse groove 51 in the bed plate 4 and held therein by the bolts 52 projecting through the anvil block and into the bed plate 4. Anvil block 50 is slotted longitudinally of the horn die 10, as at 53, to receive the V block 54 which is disposed immediately below the free end of the horn die 10. The V block 54 is held on the anvil block 50 by bolt 55 projected upward through t-he anvil and threaded int-o the V block.

The horn punch is similarly constructed of a cylindrical member 11 on the free end of which is placed the piercing punch which is formed in the shape of the slot that is to be pierced in the tube v44. This piercing punch 60 is fitted into arecess 61 in the free end of the member 11, and positioned in there by dowels 62 which are fitted into dowel holes 63 in the member 11 and dowel holes 64 in the piercing punch. The punch member is held on the end of the member 11 and in the socket 61 by bolts 65 whichproject through it and into threaded openings in the end of the member 11. The piercing punch 60 is preferably made of hardened tool steel and is formed with its lower face concave so that the pressureis applied to the tubing 44 around the periphery of the slot before it is applied to the metal at the interior of the slot, this concavity of the lower surface of the punch being shown at 66, Figure 7.

In the upper surface of the member 11 I have inserted a hard steel pressure block which contains a pocket into which the pressure pin is fitted to apply pressure to the horn punch to force the punch member 60 through the walls of the tubing 44. The pressure pin 71 is carried by the holder plate 46, being held therein by the set screw 72. I have also provided centering blocks or pins 73 and 74 which are formed as set screws threaded into the upper surface of the member 11. The heads of these set screws are shaped to engage the edges of the slots in the tube 44 to position the tube on the punch definitely with respect to that slot.

The anvil blocl; 50 which is disposed beneath the horn die 10 also extends beneath the horn punch 11 and serves as a mounting plate for the external die which registers with the piercing punch 60 of the horn punch 11.

lll() The die 80 is set into a recess 8l in the anvil block and held therein by the bevel wedge 82 and by the set screws 83 which engage that wedge to firmly clamp it against the sloping surface of the die block 80. The die block 8() is made of tempered steel and contains an opening conforming to the shape of the piercing block 60, the walls of which opening are tapered slightly with the wider portion at the bottom, so that the slugs of metal punched out of the tube 44 by the piercing block will fall through the die and through the slot 84 in the anvil plate 50 and the slot 85 in the bed plate 4 through which. latter slot they fall out of the machine.

On the opposite ends of the external die I have provided blocks 90 and 91 which have semi-circular depressions 92 formed in their upper edges. These blocks are held on the die 80 in any preferred manner such as by stud bolts 94. The blocks guard the die against being struck by the end of the tube as it is being slipped over the punch, and the semi-circular depressions aid in rigidly supporting the tube in the press during the operation of the punch.

In the operation of the punch press herein disclosed, the blank cylindrical tubes 44 shown in Figure 9 are placed over the horn die l0, one at a time, being pushed thereon until their ends engage the guide block 30. The press is .then operated to cause it to lower its plunger 3 and since the supporting block 46 is attached to this plunger it and the piercing die 42 and the pressure pin .71 are likewise lowered. The piercing die 42 engages the outer surfaces of the tube 44 pressing thatl tube firmly down against the upper surface of the horn die 10. Since the horn die is pivotally mounted and held in its uppermost position by the spring 14, the pressure of the piercing punch 42 forces the die and the tube 44 downward until the lower surface of the tube nests in the V block 54. Further movement of the piercing die 42 causes it to shear the wall of the tube 44 to pierce a circular opening 95, Figure l() in that wall. The slug that has been removed from the wall of the tubing falls through the die 4() and the slot 45 coming to rest at the bottom of that slot against the opposite surface of the tube.

The tube is then removed from the horn die l0 and placed over the horn punch ll. The end of the tube is again brought to bear againstthe die block 30 and the pressure pin 71 is brought into alignment with the hole 95 that has just been punched in the wall cf the tube 44.

The press is then reoperated and the pressure pin caused to descend through the hole in the tube 44 to engage the pressure block 70 in the upper surface of the horn punch ll. The horn punch being likewise pivotally mounted is forced downward until the piercing block 60 engages the lower surface of the tube 44, and forces that surface squarely against the external die 80. Further movement of the punch ll forces the piercing block 60 through the Wall of the tube and shears that wall to form a slot 96, Figure ll corresponding in shape to the shape of the punch and die. rlhe slugs thus cut out of the wallof the tube fall through the slot 84 and 85 and out of the machine.

The machine is released to cause the plunger 3 to rise and remove the pressure pin 7l from the pressure block 70, and the tube 44 is rotated through an arc of 180 to bring the slot that has been pierced to the upper side of the tube. rlhe heads of the centering screws 73 and 74 are brought into engagement with the ends of the slot, thereby delinitely locating the tube on the punch l1 endwise and laterally. The press is again reoperated to cause the plunger' 3 to be lowered, the operation of the horn die ll and piercing block 60 being the same as before to again shear a slot in the walls of the tube 44 which latter slot is exactly 180 from the first slot.

The tube that has been so slotted is removed from the machine and in the process of the manufacture of axle housing, as disclosed in my above copending application, serves as a blank to be fed into subsequent machines used in the various steps in the formation of a. housing as disclosed in said copending application.

lVhile the machine disclosed and the process described particularly relate to a step in the process of formation of axle housing, obviously the machine is not limited to such purposes and by suitable design of dies and punches can be used to slot tubing for other purposes. l am not, therefore, to be limited to the specific d-etails of the disclosure, but rather I am to be limited only by the scope of the appended claims. Obviously there are many modifications and adaptations which can be made by one skilled in the art without departing from the scope of the appended claims.

What I claim is:

l. In a tube slotting machine, a horn punch comprising an arm pivoted at one of its ends for movement about an axis disposed transversely of its axis and having its free end disposed adjacent a bed plate, an external die fixed on said bed plate in registration with said punch, a pressure pin adjacent said die and means for moving said pin into engagement with the punch, said means exerting a pressure on the punch through the pin in a direction normal to the axis of the arm to thereby move the punch about said pivotal axis into said die.

2. ln a tube slotting machine, a horn punch pivoted at one of its ends and having its free end disposed adjacent a bed plate, said horn punch being circular to Alit within the perforated tube that is to be slotted by it, an

externa-l die mounted on said bed plate in registration with said punch but spaced away therefrom sufficiently to permit placing the tube wall therebetween, a pressure pin registering with the perforation in said tube to center the tube on the punch, and means for operating said pressure pin to operate said punch.

3. In a tube slotting machine, an anvil shaped to conform to the outside shape of the tubing that is to be slotted in the machine, a horn die pivoted at one end of said anvil and projecting over it, an external punch registering with said die, means for guiding a tube that has been slipped over said die, means for operating said punch to pierce said tube, said die and tube being moved about the die pivot to nest the tube in said anvil, and means for 'raising said die and tube upon the rerelease of said punch operating means.

4. In a tube slotting machine, an anvil shaped to conform to the outside shape of the tubing that is to be slotted in the machine, a horn die pivoted at one end of said anvil and projecting over it, an external punch registerino' with said die, means for guiding a tube that has been slipped over said die, means for operating said punch to pierce said tube, said die and tube being moved about the die pivot to rest the tube in said anvil, and spring means for raising said die and tube upon the release of said punch operating means.

5. In a tube slotting machine, a horn die and a horn punch pivoted at one of their ends and extended parallel therefrom, an anvil having two arcuate seats, one disposed beneath the free end of the die and the other beneath the free end of the punch, an external die fitted in said latter seat to register with said punch, an external punch registering with said horn die, means for operating said punches, and means disposed between said horn die and horn punch adjacent their pivoted ends for gauging the position of tubes that have been tted over them.

6. In a machine for forming diametrically opposite slots in a tube, a pair of supporting blocks having parallel fiat faces, a bar having parallel fiat faces registering between said blockI faces, a pin projected through the blocks and bar to pivotally support the bar for movement about a horizontal axis, said bar being cylindrical adjacent its free end, a punch plate located on the free end of said bar by dowel pins and held thereon by stud bolts threaded into the bar, a stationary die with which said plate registers, locating means disposed on said bar diametrically opposite said punch plate, a. spring mounted on said supporting blocks and enga-ging said bar to hold its free end away from said die, and means for operating said bar about its pivot to force said plate through a tube of metal placed between it and said die to pierce that tube, said locating means being of a shape to properly register with the slot thus formed in the tube when the tube is rotated through 180.

7. In a tube slotting machine, a pair of supporting blocks having parallel flat faces, a bar having parallel fiat faces registering between said block faces, a pin projected through the blocks and bar to pivotally support the bar, a cylindrical portion of said bar for rotation about a horizontal axis adjacent its free end, a punch plate located on said free end by dowel pins and held thereon by stud bolts threaded into the bar, a stationary die with which said plate registers, a hardened steel socket inserted in said bar on the side opposite to said plate and centrally of it, and means engaging said socket for operating said bar about its pivot to force said plate through a tube placed between it and said die to pierce that tube.

8. The method of slotting a tube which comprises, punching a working hole in one side of it by shearing the metal of the tube inwardly, punching a slot in the opposite side of the tube by shearing the metal of that side outwardly of the tube, rotating the tube to an angle of 1800, and punching a slot in the irst side of the tube by shearing the metal of that side outwardly of the tube. Y

9. The method of slotting a tube which comprises, punching a working hole in one side of the tube by shearing the metal of the tube inwardly, punching a slot in the opposite side of thetube by shearing the metal of the tube outwardly, rotating the tube throuO'h an angle of 180, centering the tube by the edges of the slot thus formed, and punching a slot in said first side of the tube by shearing the metal of the tube outwardly.

10. The method of slotting a tube which comprises, locating the tube longitudinally with respect to a shear by engaging one of its ends against a stop, punching a working hole through one side of the tube by shearing the metal of that side inwardly of the tube, locating the tube longitudinally and circumferentially with respect to the boundary of that working hole, punching a slot in the opposite side of the tube by shearing the metal of that side outwardly of the tube, relocating the tube with respect to the boundaries of that slot, and punching a slot in said first side of the tube by shearing the metal of that side outwardly of the tube.

In witness whereof, I hereuntosubscribe my name this 26th day of December, 1929.

GEORGE SPATTA. 

